Flat electric match

ABSTRACT

A flat electric match includes a substrate having a surface. A first electrical lead and a second electrical lead each having an end, are carried by the substrate on the surface. The ends of the electrical leads are spaced apart on the surface. A bridge wire is coupled between the ends of the electrical leads and carried by the substrate on the surface. A pyrotechnic material is carried by the substrate on the surface, with at least a portion of the pyrotechnic material contacting the bridge wire.

FIELD OF THE INVENTION

This invention relates to pyrotechnic devices.

More particularly, the present invention relates to electric matches.

BACKGROUND OF THE INVENTION

Electric matches are well known in the art of explosives and pyrotechnic devices. An electric match is most often employed by insertion into a fuse, detonator, or charge and is the ignition source. The electric match ignites the detonating charge or the fuse, which then ignites the main charge or pyrotechnic device. Ignition of the electric match is accomplished by providing an electrical charge across two insulated wires coupled at an end by a resistive bridge wire. The bridge wire is heated by the electrical current which, in turn, ignites a pyrotechnic coating. The ignition of the pyrotechnic coating then ignites a fuse, detonating charge, and the like.

Electric matches are commonly formed by dipping the end of the leads with the bridge wire into a slurry of pyrotechnic material. While an effective and inexpensive device, an electric match has some problems. The bridge wire is generally soldered to the ends of the two leads, forming weak points. The leads are typically supported by an insulating header through which the ends of the leads extend and which separates and holds the leads in position relative one another. However, the loose ends between which the bridge wire is connected can flex and move. During fabrication or use, this flexing and moving of the ends of the leads can adversely effect the attachment and electrical coupling of the bridge wire. If either end of the bridge wire is separated or otherwise electrically isolated from the associated lead, such as during the dipping process, the device is rendered inoperable.

Another problem associated with electric matches is that the amount of pyrotechnic material coating the bridge wire is very limited. The fragility of the bridge wire limits its size and the amount of pyrotechnic material that can be carried. Due to this limitation, electric matches are employed to ignite a secondary or detonating charge, and are not themselves a detonating charge.

It would be highly advantageous, therefore, to remedy the foregoing and other deficiencies inherent in the prior art.

An object of the present invention is to provide a more robust and reliable electric match.

Another object of the present invention is to provide an electric match that can carry a larger pyrotechnic charge.

Yet another object of the present invention is to provide an electric match which can support multiple layers of pyrotechnic material.

And another object of the present invention is to provide an electric match that can employ pyrotechnic materials on opposing sides.

SUMMARY OF THE INVENTION

Briefly, to achieve the desired objects and advantages of the instant invention, provided is a flat electric match. The flat electric match includes a substrate having a surface, a first electrical lead having an end, and a second electrical lead having an end. The first electrical lead and the second electrical lead are carried by the substrate on the surface. The end of the first electrical lead is spaced from the end of the second electrical lead. A bridge wire is coupled between the ends of the first electrical lead and the second electrical lead. The bridge wire is carried by the substrate on the surface. A pyrotechnic material is carried by the substrate on the surface with at least a portion of the pyrotechnic material contacting the bridge wire.

In another aspect, a second bridge wire is electrical coupled to and extends between the first electrical lead and the second electrical lead, spaced from the bridge wire, and contacting at least a portion of the pyrotechnic material

In yet another aspect, an electric power source is coupled to second ends of the first lead and the second lead, supplying an electric current to the bridge wire on demand.

In a further aspect of the present invention, the flat electric match includes the substrate having a second surface with a third electrical lead having an end thereon. The third electrical lead is carried by the substrate on the second surface. A fourth electrical lead having an end is carried by the substrate on the second surface with the end of the third electrical lead spaced from the end of the fourth electrical lead. A second bridge wire is coupled between the third electrical lead and the fourth electrical lead. The second bridge wire is carried by the substrate on the second surface. A second pyrotechnic material is carried by the substrate on the second surface with at least a portion contacting the second bridge wire.

In yet a further aspect of the present invention, the flat electric match includes the substrate having a second surface. At least one bridge wire is carried by the substrate on the second surface with the at least one bridge wire electrically coupled between the first electrical lead and the second electrical lead. A second pyrotechnic material is carried by the substrate on the second surface, with at least a portion of the second pyrotechnic material contacting the at least one bridge wire.

BRIEF DESCRIPTION OF THE DRAWINGS

Specific objects and advantages of the instant invention will become readily apparent to those skilled in the art from the following detailed description of a preferred embodiment thereof taken in conjunction with the drawings, in which:

FIG. 1 is a top plan view of a flat electric match according to the present invention;

FIG. 2 is a sectional end view of the match of FIG. 1;

FIG. 3 is a top plan view of another embodiment of a flat match according to the present invention;

FIG. 4 is a top plan view of yet another embodiment of a flat match according to the present invention;

FIG. 5 is a perspective view of an addition to the embodiment of FIG. 4, illustrating a circuit and pyrotechnic material on an opposing surface of a substrate; and

FIG. 6 is an end view of the flat match of FIG. 5.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Turning now to the drawings in which like reference characters indicate corresponding elements throughout the several views, attention is first directed to FIG. 1 which illustrates a top plan view of a flat electric match generally designated 10. Match 10 includes a substrate 12 having a surface 14. It will be understood that substantially any substrate can be employed for the present invention and is intended to provide support to the various remaining elements of match 10. The substrate is insulative or has insulating portions to which the leads and bridge wire are attached. A lead 15 and a lead 16 are carried by substrate 12 on surface 14. Leads 15 and 16 include ends 18 and 19 respectively coupled to an electrical source such as a battery and the like. Opposing ends 20 and 22 of leads 15 and 16 are spaced apart on surface 14 of substrate 12 and electrically coupled by a bridge wire 25 having an end 27 coupled to end 20 and an end 28 coupled to end 22. Leads 15 and 16, and bridge wire 25 form an electrical circuit when completed by an electrical power source such as a battery or the like, allowing current to flow through bridge wire 25 on demand.

Leads 15 and 16, in this embodiment, are conductive wires 30 having an insulating layer 32 and extend along surface 14, providing support along their entire length. Bridge wire 25 is also supported by surface 14 of substrate 12, thus removing any potential for flexing or movement of leads 15 and 16 relative bridge wire 25. It is noted here that while leads 15 and 16 can be insulated wires carried by substrate 12 on surface 14, the leads can also be formed on the substrate by depositing, sputtering, painting, embedding, printing, etc., conductive materials on surface 14. This is also the case for bridge wire 25. It should also be noted that leads 15 and 16 need not be positioned in parallel. It is sufficient that ends 20 and 22 are spaced apart but in sufficient proximity to be electrically coupled by bridge wire 25.

A pyrotechnic material 35 can then be applied to bridge wire 25 by dropping, brushing or otherwise covering, or at least contacting, a portion of bridge wire 25 with a slurry of pyrotechnic material 35. There are a multitude of different pyrotechnic materials known in the art, any of which can be used in the present invention. Due to the large number and well known nature and fabrication of different pyrotechnic materials and compositions, a detailed description thereof has been omitted from the present disclosure. The amount of material 35 added is not limited by the size or strength of bridge wire 25, as the weight and volume of the pyrotechnic charge is fully supported by surface 14 of substrate 12. Once a layer of material has dried or hardened, subsequent layers can be applied if desired to form a pyrotechnic charge of multiple layers 35 a, 35 b, and 35 c, as illustrated in FIG. 2. In this manner, an actual detonating charge can be provided by the electric match as opposed to only being used to ignite a detonating charge. Thus, flat electric match 10 can be used in a manner similar to conventional electric matches to ignite a fuse or detonating charge, or in a novel manner as a detonating charge itself.

Turning now to FIG. 3, another embodiment of a flat electric match 40 according to the present invention is illustrated. Match 40 is similar to match 10 as it includes a substrate 42 having a surface 44. Match 40 also includes a lead 45 and a lead 46 carried by substrate 42 on surface 44. Leads 45 and 46 include ends 48 and 49, respectively, coupled to an electrical source such as a battery or the like. Opposing ends 50 and 52 of leads 45 and 46 are spaced apart on surface 14 of substrate 12 and electrically coupled by a bridge wire 55 having an end 57 coupled to end 50 and an end 58 coupled to end 52. The difference is the inclusion of additional bridge wire 60 extending between leads 45 and 46 spaced from bridge wire 55. Thus, multiple bridge wires, two or more, are provided for redundancy and possibly for uniform ignition of a large pyrotechnic charge 62. By employing multiple bridge wires, the failure of one bridge wire does not render the device inoperable. As with flat match 10, match 40 can employ insulated wires as leads 45 and 46. In this case, leads 45 and 46 each include a conductive wire 64 having an insulating layer 65, and which extend along surface 44.

Turning now to FIG. 4, another embodiment of a flat match, generally designated 110 is illustrated. Match 110 includes a substrate 112 having a surface 114. It will be understood that substantially any substrate can be employed for the present invention and is intended to provide support to the various remaining elements of match 110. The substrate is insulative or has insulating portions to which the leads and bridge wire are attached. A lead 115 and a lead 116 are carried by substrate 112 on surface 114. In the present embodiment, leads 115 and 116 are conductive material printed onto surface 114, although it is understood that they can be deposited, painted, adhered or the like, onto surface 114. Leads 115 and 116 include ends 118 and 119, respectively, which are coupled to a power source for selective activation of match 110. Leads 115 and 116 are spaced apart on surface 114 of substrate 112 and electrically coupled by bridge wires 124 and 125 each having an end 127 coupled to lead 115 and an end 128 coupled to lead 116. Leads 115 and 116, and bridge wires 124 and 125 form an electrical circuit when completed by an electrical power source such as a battery or the like, allowing current to flow through bridge wires 124 and 125 on demand.

A pyrotechnic material 132 can then be applied to bridge wires 124 and 125 by dropping, brushing or otherwise covering, or at least contacting, a portion of bridge wires 124 and 125 with a slurry of pyrotechnic material 132. The amount of material 132 added is not limited by the size or strength of bridge wires 124 and 125, as the weight and volume of the pyrotechnic charge is fully supported by surface 114 of substrate 112. Once a layer of material has dried or hardened, subsequent layers can be applied if desired to form a pyrotechnic charge of multiple layers.

Referring now to FIGS. 5 and 6, a surface 134 of substrate 112 opposing surface 114 has, in the preferred embodiment illustrated, added thereon a second electrical circuit. Thus match 110 can be modified to include a lead 135 and a lead 136 carried by substrate 112 on surface 134. In the present embodiment, leads 135 and 136 are conductive material printed onto surface 134. Leads 135 and 136 include ends 138 and 139, respectively, which are coupled to a power source for selective activation of match 110. Leads 135 and 136 are spaced apart on surface 134 of substrate 112 and electrically coupled by bridge wires 144 and 145 each having an end 147 coupled to lead 135 and an end 148 coupled to lead 136. Leads 135 and 136, and bridge wires 144 and 145 form an electrical circuit when completed by an electrical power source such as a battery or the like, allowing current to flow through bridge wires 144 and 145 on demand. The power source may be the same as coupled to leads 115 and 116, or a separate source to permit delayed or timed ignition of either or both circuits of match 110.

As another embodiment, the second electrical circuit on surface 134 can be formed of one or more bridge wires 144 and 145 coupled to leads 115 and 116 of the electrical circuit on surface 114 by interconnecting electrical vias (known in the circuit board industry) that run through substrate 112. In this manner, bridge wires 144 and 145 are coupled by vias to leads 115 and 116 to form an electrical circuit when completed by an electrical power source such as a battery or the like, allowing current to flow through bridge wires 144 and 145 on demand.

A pyrotechnic material 150 can then be applied to bridge wires 144 and 145 by dropping, brushing or otherwise covering, or at least contacting, a portion of bridge wires 144 and 145 with a slurry of pyrotechnic material 150. Materials 150 can be the same as or different than pyrotechnic material 132 carried on surface 114. In this manner, match 110 can have multiple pyrotechnic ignitions of different materials at the same or different times, as well as an increased volume of materials.

Various changes and modifications to the embodiments herein chosen for purposes of illustration will readily occur to those skilled in the art. To the extent that such modifications and variations do not depart from the spirit of the invention, they are intended to be included within the scope thereof, which is assessed only by a fair interpretation of the following claims.

Having fully described the invention in such clear and concise terms as to enable those skilled in the art to understand and practice the same, the invention claimed is: 

1. A flat electric match comprising: a substrate having a surface; a first electrical lead having an end, the first electrical lead carried by the substrate on the surface; a second electrical lead having an end, the second electrical lead carried by the substrate on the surface with the end of the first electrical lead spaced from the end of the second electrical lead; a bridge wire coupled between the first electrical lead and the second electrical lead, the bridge wire carried by the substrate on the surface; and a pyrotechnic material carried by the substrate on the surface, at least a portion of the pyrotechnic material contacting the bridge wire.
 2. A flat electric match as claimed in claim 1 further including a second bridge wire electrical coupled to and extending between the first electrical lead and the second electrical lead, spaced from the bridge wire, and contacting at least a portion of the pyrotechnic material.
 3. A flat electric match as claimed in claim 1 wherein the first lead and the second lead are insulated wires.
 4. A flat electric match as claimed in claim 1 wherein the first lead and the second lead are formed on the surface of the substrate.
 5. A flat electric match as claimed in claim 1 wherein the pyrotechnic material is multilayered.
 6. A flat electric match as claimed in claim 1 further comprising: the substrate having a second surface; a third electrical lead having an end, the third electrical lead carried by the substrate on the second surface; a fourth electrical lead having an end, the fourth electrical lead carried by the substrate on the second surface with the end of the third electrical lead spaced from the end of the fourth electrical lead; a second bridge wire coupled between the third electrical lead and the fourth electrical lead, the second bridge wire carried by the substrate on the second surface; and a second pyrotechnic material carried by the substrate on the second surface, at least a portion of the second pyrotechnic material contacting the second bridge wire.
 7. A flat electric match as claimed in claim 6 further including a third bridge wire electrical coupled to and extending between the first electrical lead and the second electrical lead, spaced from the bridge wire, and contacting at least a portion of the pyrotechnic material, and a fourth bridge wire electrical coupled to and extending between the third electrical lead and the fourth electrical lead spaced from the second bridge wire, and contacting at least a portion of the second pyrotechnic material.
 8. A flat electric match as claimed in claim 1 further comprising: the substrate having a second surface; at least one bridge wire carried by the substrate on the second surface, the at least one bridge wire electrically coupled between the first electrical lead and the second electrical lead; and a second pyrotechnic material carried by the substrate on the second surface, at least a portion of the second pyrotechnic material contacting the at least one bridge wire.
 9. A flat electric match comprising: a substrate having a surface; a first electrical lead having a first end and a second end, the first electrical lead carried by the substrate on the surface; a second electrical lead having a first end and a second end, the second electrical lead carried by the substrate on the surface with the first end of the first electrical lead spaced from the first end of the second electrical lead; a bridge wire coupled between the first electrical lead and the second electrical lead, the bridge wire carried by the substrate on the surface; a pyrotechnic material carried by the substrate on the surface, at least a portion of the pyrotechnic material contacting the bridge wire; and an electric power source coupled to the second ends of the first lead and the second lead, supplying an electric current to the bridge wire on demand.
 10. A flat electric match as claimed in claim 9 further including a second bridge wire electrical coupled to and extending between the first electrical lead and the second electrical lead, spaced from the bridge wire, and contacting at least a portion of the pyrotechnic material.
 11. A flat electric match as claimed in claim 9 wherein the first lead and the second lead are insulated wires.
 12. A flat electric match as claimed in claim 9 wherein the first lead and the second lead are formed on the surface of the substrate.
 13. A flat electric match as claimed in claim 9 wherein the pyrotechnic material is multilayered.
 14. A flat electric match as claimed in claim 9 further comprising: the substrate having a second surface; a third electrical lead having a first end and a second end, the third electrical lead carried by the substrate on the second surface; a fourth electrical lead having a first end and a second end, the fourth electrical lead carried by the substrate on the second surface with the first end of the third electrical lead spaced from the first end of the fourth electrical lead; a second bridge wire coupled between the third electrical lead and the fourth electrical lead, the second bridge wire carried by the substrate on the second surface; a second pyrotechnic material carried by the substrate on the second surface, at least a portion of the pyrotechnic material contacting the second bridge wire; and an electric power source coupled to the second ends of the third lead and the fourth lead, supplying an electric current to the second bridge wire on demand.
 15. A flat electric match as claimed in claim 14 further including a third bridge wire electrical coupled to and extending between the first electrical lead and the second electrical lead, spaced from the bridge wire, and contacting at least a portion of the pyrotechnic material, and a fourth bridge wire electrical coupled to and extending between the third electrical lead and the fourth electrical lead spaced from the second bridge wire, and contacting at least a portion of the second pyrotechnic material.
 16. A flat electric match as claimed in claim 9 further comprising: the substrate having a second surface; at least one bridge wire carried by the substrate on the second surface, the at least one bridge wire electrically coupled between the first electrical lead and the second electrical lead; and a second pyrotechnic material carried by the substrate on the second surface, at least a portion of the second pyrotechnic material contacting the at least one bridge wire. 